Over the years, numerous types of utility knives have been developed. Many with specific applications in mind, such as cutting wallpaper, and many directed to specific problems, such as ease of use and operation.
Wallpaper cutting devices are generally utility knives adapted for neatly cutting wallpaper during application. The overriding characteristic of such a device is a razor sharp blade. Wallpaper cutting devices have also evolved for specific application to particular circumstances. For instance, wallpaper cutting devices have been devised which utilize shaped blades particularly adapted to the type of wallpaper to be cut. Similarly, wallpaper cutting devices have been devised which not only cut the wallpaper, but perform a further task.
In this regard, the art associated with wallpaper cutting devices has seen the introduction of numerous cutting devices adapted specifically for cutting wallpaper along irregular edges. These devices have included, inter alia, rigid guides and wheeled guides for directing the cutting device along an edge dictated by the wall surface itself. These devices though, for various reasons, have failed to provide satisfactory results and have resultingly not been widely accepted.
Generally, the major shortcoming of these previously developed guided devices is their lack of versatility. These devices have generally been superior at solving particular problem. For example a device may be superior at cutting a straight line, and correspondingly, poor at cutting a curved line. Or, in the alternative, a device may be superior at cutting a curved line, and unable to obtain a clean cut along a straight line. Finally, there are devices uniquely adapted for obtaining extremely clean cuts, but whose guides leave something to be desired, whether the line be straight or curved.
The utility knives of the prior art also include devices which are directed to ease of use and operation. Generally, utility knives require disassembly in order for a worn blade to be replaced. This obviously is a significant shortcoming, especially if the user is in a position where such replacement is difficult or impossible. In this regard, the prior art has developed segmentable and detachable blades. Unfortunately, the devices which use a segmentable blade eventually require blade replacement and accordingly, only postpone the problems incident thereto. Similarly, the device with detachable blades utilize attachment mechanisms which are prone to breakage and accidental detachment.
These attachment mechanisms are also normally a feature of a blade adjustment mechanism. This dual function, while at first glance worthwhile, is in fact detrimental. Such a dual function often results in the blade coming free during use or during blade adjustment. Further, such dual function results in a device which is relatively easily disabled, as a result of one part performing too many tasks. In other words, if either function becomes inoperative as a result of breakage or malfunction, the entire device generally becomes disabled.